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CONNECT(2) FreeBSD System Calls Manual CONNECT(2)
NAMEconnect -- initiate a connection on a socket
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS#include <sys/socket.h>
intconnect(ints, conststructsockaddr*name, socklen_tnamelen);
DESCRIPTION
The s argument is a socket. If it is of type SOCK_DGRAM, this call spec-
ifies the peer with which the socket is to be associated; this address is
that to which datagrams are to be sent, and the only address from which
datagrams are to be received. If the socket is of type SOCK_STREAM, this
call attempts to make a connection to another socket. The other socket
is specified by name, which is an address in the communications space of
the socket. namelen indicates the amount of space pointed to by name, in
bytes; the sa_len member of name is ignored. Each communications space
interprets the name argument in its own way. Generally, stream sockets
may successfully connect() only once; datagram sockets may use connect()
multiple times to change their association. Datagram sockets may dis-
solve the association by connecting to an invalid address, such as a null
address.
RETURN VALUES
The connect() function returns the value 0 if successful; otherwise the
value -1 is returned and the global variable errno is set to indicate the
error.
ERRORS
The connect() system call fails if:
[EBADF] The s argument is not a valid descriptor.
[EINVAL] The namelen argument is not a valid length for the
address family.
[ENOTSOCK] The s argument is a descriptor for a file, not a
socket.
[EADDRNOTAVAIL] The specified address is not available on this
machine.
[EAFNOSUPPORT] Addresses in the specified address family cannot be
used with this socket.
[EISCONN] The socket is already connected.
[ETIMEDOUT] Connection establishment timed out without establish-
ing a connection.
[ECONNREFUSED] The attempt to connect was forcefully rejected.
[ECONNRESET] The connection was reset by the remote host.
[ENETUNREACH] The network is not reachable from this host.
[EHOSTUNREACH] The remote host is not reachable from this host.
[EADDRINUSE] The address is already in use.
[EFAULT] The name argument specifies an area outside the
process address space.
[EINPROGRESS] The socket is non-blocking and the connection cannot
be completed immediately. It is possible to select(2)
for completion by selecting the socket for writing.
[EINTR] The connection attempt was interrupted by the delivery
of a signal. The connection will be established in
the background, as in the case of EINPROGRESS.
[EALREADY] A previous connection attempt has not yet been com-
pleted.
[EACCES] An attempt is made to connect to a broadcast address
(obtained through the INADDR_BROADCAST constant or the
INADDR_NONE return value) through a socket that does
not provide broadcast functionality.
[EAGAIN] An auto-assigned port number was requested but no
auto-assigned ports are available. Increasing the
port range specified by sysctl(3) MIB variables
net.inet.ip.portrange.first and
net.inet.ip.portrange.last may alleviate the problem.
The following errors are specific to connecting names in the UNIX domain.
These errors may not apply in future versions of the UNIX IPC domain.
[ENOTDIR] A component of the path prefix is not a directory.
[ENAMETOOLONG] A component of a pathname exceeded 255 characters, or
an entire path name exceeded 1023 characters.
[ENOENT] The named socket does not exist.
[EACCES] Search permission is denied for a component of the
path prefix.
[EACCES] Write access to the named socket is denied.
[ELOOP] Too many symbolic links were encountered in translat-
ing the pathname.
[EPERM] Write access to the named socket is denied.
SEE ALSOaccept(2), getpeername(2), getsockname(2), select(2), socket(2),
sysctl(3), sysctl(8)HISTORY
The connect() system call appeared in 4.2BSD.
FreeBSD Ports 11.2 August 18, 2016 FreeBSD Ports 11.2